Fact Sheet: Announcement of Completion of EPA's Third Six-Year Review of Existing Drinking Water Standards United States Environmental Protection Agency The Safe Drinking Water Act (SDWA) requires EPA to review each National Primary Drinking Water Regulation (NPDWR) at least once every six years and revise them, if appropriate. The purpose of the review, called the Six-Year Review, is to identify those NPDWRs for which current health effects assessments, changes in technology, and/or other factors provide a health or technical basis to support a regulatory revision that will maintain or strengthen public health protection. Questions and Answers 1. What is the Environmental Protection Agency (EPA) announcing? In December 2016, the Agency announced the completion of its third review of existing NPDWRs (i.e., the Six-Year Review 3). Based on the Agency's detailed review of 76 NPDWRs, the Agency determined that 68 of them remain appropriate (i.e., do not need to be revised) and that eight NPDWRs are candidates for regulatory revision. These eight NPDWRs are included in the Stage 1 and the Stage 2 Disinfectants and Disinfection Byproducts Rules, the Surface Water Treatment Rule, the Interim Enhanced Surface Water Treatment Rule and the Long Term 1 Enhanced Surface Water Treatment Rule. The eight NPDWRs are chlorite, Cryptosporidium, Giardia lamblia, haloacetic acids (HAA5), heterotrophic bacteria, Legionella, total trihalomethanes (TTHM) and viruses. In addition to 76 NPDWRs, this review includes 12 other NPDWRs that did not need a detailed review because of recent, ongoing, or pending regulatory actions. 2. Why did EPA conduct a review of the National Primary Drinking Water Regulations (NPDWRs)? The 1996 Safe Drinking Water Act (SDWA) Amendments require EPA to conduct a review of existing NPDWRs every six years and determine which, if any, need to be revised. This requirement is contained in Section 1412(b)(9) of SDWA, which reads: The Administrator shall, not less often than every 6 years, review and revise, as appropriate, each national primary drinking water regulation promulgated under this title. Any revision of a national primary drinking water regulation shall be promulgated in accordance with this section, except that each revision shall maintain, or provide for greater, protection of the health ofpersons. 3. What NPDWRs are covered by this action? The Six-Year Review process only applies to NPDWRs (i.e., currently regulated contaminants/parameters). Unregulated contaminants, such as those listed on the Contaminant Candidate List (CCL), are not covered by the Six-Year Review. The current review specifically focused on the 76 regulations promulgated prior to August 2008. The Agency included 12 other NPDWRs (e.g., lead, copper, trichloroethylene (TCE) and tetrachloroethylene (PCE)) in the review. However, these regulations did not need a detailed assessment because they are the subject of recent, ongoing, or pending rulemaking activity. 4. How did EPA review the NPDWRs under Six-Year Review 3? A detailed description of the process the Agency used to review the NPDWRs is documented in the "EPA Protocol for the Third Review of Existing National Primary Drinking Water Regulations." The foundation of this protocol was developed for the Six-Year Review 1 based on the recommendations of the National Office of Water (4607M) 815-F-16-010 December 2016 1 ------- Drinking Water Advisory Council. The Six-Year Review 3 process is very similar to the process implemented during the Six-Year Review 1 and the Six-Year Review 2, with some clarifications to the elements related to the review of NPDWRs included in the Microbial and Disinfection Byproducts Rules. The protocol for the Six-Year Review 3 is broken down into a series of questions that can inform a decision about the appropriateness of revising an NPDWR. These questions are structured into a decision tree related to the following review elements considered for each NPDWR during the Six-Year Review 3: initial review, health effects, analytical feasibility, occurrence and exposure, treatment feasibility, risk balancing and other regulatory revisions. Figure 1. Six-Year Review Protocol Overview and Review Outcomes Yes No No •Uncertain - emerging No Yes No * Contaminants with an HEA in process that have an MCL based on practical quantitation limit and are greaterthan MCLG are passed to the next question to evaluate potential to revise the MCL. NPDWR reviewed in recent or ongoing action? NPDWRs Under Review assessment (HEA) in process or planned? * Data sufficient to support regulatory revision? New information to suggest possible changes (i.e... to an MCLG, MCL, Treatment Technique and/or other regulatory revisions)? Meaningful opportunity for health risk reduction for persons served by PWSs and-'or cost savings while maintaining'improving public health protection? 5. What are the overall review results for Six-Year Review 3? Based on its review, EPA finds that eight NPDWRs are candidates for regulatory revision. These eight NPDWRs are chlorite, Cryptosporidium, Giardia lamblia, HAA5, heterotrophic bacteria, Legionella, TTHM, and Viruses. EPA believes the remaining 68 NPDWRs are not appropriate for revision due to one or more of the following reasons: • Regulatory action - recently completed, ongoing or pending. The NPDWR was recently completed, is being reviewed in an ongoing action, or is subject to a pending action. • Ongoing or planned health effects assessment. The NPDWR has an ongoing health effects assessment (i.e., especially for those NPDWRs with an MCL set at the MCLG or where the MCL is based on the SDWA cost benefit provision), or EPA is considering whether a new health effects assessment is needed. • No new information. EPA did not identify any new, relevant information that indicates changes to the NPDWR. Office of Water (4607M) 815-F-16-010 December 2016 2 ------- • Low priority and/or no meaningful opportunity. New information indicates a possible change to the MCLG and/or MCL but changes to the NPDWR are not warranted due to one or more of the following reasons: (1) possible changes present negligible gains in public health protection; (2) possible changes present limited opportunity for cost savings while maintaining the same or greater level of health protection; and (3) possible changes are a low priority because of competing workload priorities, limited return on the administrative costs associated with rulemaking and the burden on states and the regulated community associated with implementing any regulatory change that would result. Table 1 lists the results of EPA's review for each of the 76 NPDWRs that received a detailed review, along with the principal rationale for the review outcomes. Table 1 also includes a list of the 12 NPDWRs that were recently completed, are being reviewed in an ongoing action, or are subject to a pending action. 6. Will EPA consider reviewing any NPDWRs before the next review cycle? If the result of an ongoing health risk assessment or the resolution of data gaps/research needs indicates that significant or compelling new information becomes available that will change the basis for an NPDWR, the Agency may decide to accelerate the review schedule for a particular NPDWR. 7. What are the next steps? The Agency requests public comment on the eight NPDWRs identified as candidates for revision, as well as other relevant comments. EPA will consider comments received as the Agency moves forward with determining whether regulatory actions are necessary for the eight NPDWRs. 8. Where can I find more information about this notice and the Six-Year Review? For information on the Six-Year Review, please visit the EPA internet website, https://www.epa.gov/dwsixyearreview. For general information on drinking water, please visit the EPA Office of Ground Water and DrinkingWater website at https://www.epa.gov/ground-water-and-drinking-water or contact the Safe Drinking Water Hotline at 1-800-426-4791. The Safe Drinking Water Hotline is open Monday through Friday, excluding legal holidays, from 10:00 a.m. to 4:00 p.m. Eastern Time. Table 1. Summary of Six-Year Review 3 Results Not Appropriate for Revision at this Time Recently completed, ongoing or pending regulatory action 1,2-Dichloroethane (Ethylene dichloride) E. coli 1,2-Dichloropropane Lead Benzene Tetrachloroethylene (PCE) Carbon Tetrachloride Total coliforms (under ADWR and RTCR) Copper Trichloroethylene (TCE) Dichloromethane (Methylene chloride) Vinyl chloride Not Appropriate for Revision at this Time2 Health effects assessment in process (as of December 2015) or contaminant Alpha/photon emitters Mercury1 Arsenic Nitrate1 Atrazine Nitrite1 Benzo(a)pyrene (PAHs) o-Dichlorobenzene1 Beta/photon emitters p-Dichlorobenzene1 Office of Water (4607M) 815-F-16-010 December 2016 3 ------- nominated for health Cadmium1 Polychlorinated biphenyls (PCBs) assessment Chromium Radium Di(2-ethylhexyl) phthalate (DEHP)1 Simazine Ethylbenzene Uranium1 Glyphosate 1,2-Dibromo-3 -chloropropane (DBCP) Dalapon No new information, NPDWR 2,4,5 -TP (Silvex) Di(2-ethylhexyl)adipate (DEHA) Antimony Dinoseb Asbestos Endrin remains Bromate Ethylene dibromide appropriate after Chloramines (under D/DBPR) Pentachlorophenol review Chlorine (under D/DBPR) Thallium Chlorine dioxide trans-1,2-Dichloroethylene Chlorobenzene (monochlorobenzene) Turbidity 1,1,1 -Trichloroethane Epichlorohydrin 1,1,2-Trichloroethane Fluoride 1,1 -Dichloroethylene Heptachlor 1,2,4-Trichlorobenzene Heptachlor epoxide 2,3,7,8-TCDD (Dioxin) Hexachlorobenzene 2,4-D Hexachlorocyclopentadiene Low priority and/or no Acrylamide Lindane Alachlor Methoxychlor meaningful Barium Oxamyl (Vydate) opportunity Beryllium Picloram Carbofuran Selenium Chlordane Styrene cis-l,2-Dichloroethylene Toluene Cyanide Toxaphene Diquat Xylenes Endothall Chlorite Heterotrophic Bacteria Candidate for Revision New information Cryptosporidium (under SWTR, IESWTR, LT1) Legionella Giardia lamblia TTHM Haloacetic Acids (HAA5) Viruses (under SWTR) 1. Contaminants nominated for Integrated Risk Information System (IRIS) assessments per SYR Protocol. 2. LT2, FBRR, and GWR also identified as not appropriate for revision at this time. See Section VI.B.4 for additional information on the results of EPA's review of these regulations. Office of Water (4607M) 815-F-16-010 December 2016 4 ------- |